FR2687417A1 - PRINTABLE SHEET INFALSIFIABLE BY MECHANICAL METHODS. - Google Patents

Abstract

The invention relates to a sheet that cannot be falsified by mechanical means. The sheet is coated, at least at the places which will bear the impressions and / or the writings to be protected, with a glossy layer which becomes matt when subjected to an action of erasing or scraping. According to the invention, the layer of the sheet is shiny, and contains coating pigments, as well as a binder. The sheet includes chemical tampering agents and / or authentication elements. Application as security paper or for banknotes.

Description

yew

  PRINTABLE SHEET INFALSIFIABLE BY MECHANICAL METHODS

  The invention relates to a security sheet or for banknotes,

  tamper-proof by mechanical methods, in particular by scrubbing or scraping.

  This sheet is particularly intended for the manufacture of security documents or valuable documents bearing coded information, for example in the form of bar codes such as checks, identity cards, passports, lottery tickets, tickets tickets for cultural or sports events, restaurant vouchers, accounting books, labels, invoices, etc. Some of these documents are protected against chemical falsification by the incorporation of chemical reagents giving colored reactions with the agents of forgery which are in particular redox, acids, bases, solvents Such documents are for example described in the patent applications FR-A-2365656, FR-A-2399505,

  FR-E-2402739, FR-A-2406027, FR-A-2427426, FR-E-2432576, EP-A-174885.

  However it is also very important to protect these documents against falsification by mechanical or physical means Indeed, fraudsters may try to modify, for example by scrubbing or scraping, the amount, the account number, the signature or the beneficiary of a check, the dates or destinations of a ticket Falsified mentions may be hand written or printed by any means of printing such as offset, rotogravure, intaglio, etc. impression that has particularly developed in recent years is the indirect electrophotographic printing, still called xerographic printing,

  such as for example printing by photocopy or laser printer.

  The conventional indirect electrophotographic process producing paper copies from a paper original is characterized by: forming on an appropriate surface an electrostatic image generated optically from the original, developing this image with a colored toner and fuse, transferring the toner image to a sheet of paper, fixing the toner to the sheet by applying heat and / or pressure.

  By extension of the electrophotographic copying system, the electronic image

  static can be generated no more optically from an original, but by means of light-emitting diodes having a converging ray similar to a laser beam, directed by the memory of a computer The laser thus reproduces on the surface of the receiver an electrostatic image from "the original" content

in the computer's memory.

  Laser or xerographic printing is therefore a very popular process for printing any type of document and in particular valuable documents such as those mentioned above including the check (called in this case letter-check).

  However, printing on the media is still pretty bad now.

  It is therefore relatively easy to falsify documents thus printed by mechanical means; the impression can be removed by erasing it or

  scratching using for example a blade.

  It is already known to highlight an attempt at physical forgery by printing on the document a frame consisting of fine lines;

  this frame is damaged during forgery.

  In the application FR-A-2 280 154 an attempt at erasure by scraping or scrubbing is evidenced by verification, visual and / or with the aid of a device, the intact state of a protective layer applied before or after printing to be protected by comparing the properties of luminance, or spectral reflection, or fluorescence between the paper and the layer and / or between the layer and the printing ink, at lengths of selected waves of a light source for verification or reading This invention uses a complicated and inflexible process This assumes that the layer is destroyed during forgery to reveal the paper support if we compare the support and the layer and requires a choice

  specific support / layer and / or printing ink / layer.

  In the patent application CA-A-2 016 046, attempts have been made to solve the problems of physical forgery of toner prints by providing a coated paper with a composition containing on the one hand a particular styrene acrylic acid copolymer which improves adhesion toner on the paper and on the other hand a dye which highlights the attempts of falsification by scraping or exfoliation Thus when a mechanical falsification is attempted the colored layer is partially destroyed and then the paper medium is observed which is generally white, this which highlights the falsification but this requires that the layer be destroyed during the

  falsification and that is made a specific choice support / colored layer.

  These proposals do not preclude the risk that a skilled fraudster erases an inscription without destroying the layer or else it needs a very friable layer, but then the layer will be easily damaged when the paper is printed or folded by In addition, these proposals link the color or the other optical characteristics of the layer providing the physical infalsification with those of the basic support and possibly those of the impressions. This restricts the possibilities of choice of the support and the layer, it is impossible to not particularly use a support and a layer

  which are of the same color or shade.

  European patent application EP-A-0 424 343, filed by International paper, describes an ion-depositable paper which can easily be used in office applications. The purpose of the invention described in this application is to avoid that the printing is removed, after having joined two parts of the printed sheet by means of an adhesive tape, it is desired to separate the two sheet parts again. It is absolutely not a security paper or a paper. The paper described and claimed in this application is a paper which is used with a polymer-based toner. This paper has a layer which comprises a polymer latex having a glass transition temperature of from about -30 ° C. + 30 OC and which has a solubility parameter of between about 8 and about 12, based on the toner binder used for printing

  In addition, the final coated paper has a matte surface.

  Therefore, this ion-depositable coated paper is such that the printing can not be torn off by adhesive tape. This result is obtained because the toner binder and the binder of the layer have a certain relative solubility. absolutely not mentioned in this patent application that one wishes a security paper and / or banknote, which is printable in any way and including any alteration of the printing (for example by scrubbing and / or scratching) is highlighted by a difference in gloss before and after falsification attempt. No. 5,045,426, filed by The Standard Register Company, discloses a security document sheet which has improved toner adhesion, which sheet is coated with a dispersion containing a styrene-acrylic acid copolymer. having a glass transition temperature of between -16.degree. and 220.degree. C. and about 1 to 5% by weight of zinc, which is a crosslinking agent for said copolymer. Like the preceding document, the purpose of this patent is to improve the resistance toner particles, these particles being more particularly fusible by heat and

pressure The layer is matte.

  The Applicant proposes to solve the problems of physical infalsification by providing a more general solution that may be suitable for any type

  support and any type of printing and / or writing.

  The object of the invention is to provide a security sheet and / or for bank notes, at least partially lying down, unfalsifiable by mechanical methods and such that falsification attempts by scrubbing or scratching are highlighted without it it is necessary to destroy the layer and that this highlighting is independent of the color or

  other optical characteristics of the support and / or prints.

  Another object of the invention is to provide a security sheet and / or for bank notes, having complete protection vis-à-vis both physical falsifications and chemical falsifications and other counterfeits. The Applicant has found that the object of the invention is achieved if the sheet is coated, at least in the places that will bear the prints and / or writings to protect, a glossy layer that becomes matte when it is

  subjected to a scrubbing action and / or scraping.

  When we try to erase a statement carried by the sheet, the layer becomes matte, and then we observe the matte / glossy contrast that highlights the attempt to falsify It is the same when trying to

to falsify a mention by scratching.

  The gloss of the layer can come from the use of a naturally shiny product or be obtained by an adequate calendering of the sheet

coated with a layer.

  Preferably the layer has a gloss, measured by the 75 degree gloss determination according to TAP method Pl 480 om-85, greater than or equal to

25.

  In a particular case of the invention, the layer contains at least coating pigments and at least one binder The pigments improve in general

the quality of printing.

  In another particular case, the layer may contain a dye (soluble or pigmentary), the color of the layer possibly being that of

basic support.

  Preferably, the sheet is coated on its entire face or both sides of

the shiny layer.

  The layer can be applied to the sheet according to the coating methods

  known paper mill or according to known printing methods.

  The base support of the sheet may be obtained by paper from a composition of cellulosic fibers only or from a mixture of cellulose fibers and synthetic fibers or from purely synthetic fibers; the composition may of course contain other additives such as, for example, mineral or organic fillers, mineral fibers, bonding agents, bacteriostatic agents, flame retardants, etc. The surface of the support may also be treated in a size press

  The support may be a nonwoven obtained by wet or dry route.

  It can also be a plastic film.

  The invention also provides a security sheet and / or for banknotes

  bank, whose support can be white or colored mass or surface.

  The invention also provides a security and / or banknote sheet comprising chemical tampering agents and / or authentication elements. Thus, a sheet having a very complete protection against falsifications is obtained. both physical and chemical and counterfeits. The support may contain in bulk and / or on the surface chemical tampering agents such as those described above; for example pyranine which gives a fluorescent yellow color under the action of an eraser pen. Many agents can be employed, but care must be taken to ensure their compatibility. The medium may contain authentication elements used for security documents such as, for example, watermarks, boards, fibers for example fluorescent, security threads etc. Authentication agents and / or authentication elements may

  also be under and / or in the glossy layer.

  The invention will be better understood with the aid of the following nonlimiting examples:

EXAMPLE 1

  A sheet of white paper is coated on each of its faces with an aqueous pigmented composition containing 5 parts of kaolin for 1 part of

  binder (latex styrene butadiene) The layer obtained is white.

  The weight of the deposited layer, in dry form, is 14 g / m 2 per side. The sheet thus coated is calendered so as to have an average gloss of 60; this measurement is made by determining the gloss at 75 degrees according to the method

TAP Pl 480 om-85.

  Each side is printed by laser printing.

  We try to erase some printed characters; the characters are partially erased, but the layer loses its brilliance (the layer is not destroyed, however). The difference in brightness of the layer at the point of falsification is thus easily observed with the naked eye. Similarly if we try to scrape with a blade some printed characters, the gloss disappears If we try to rub with a woolen cloth part matte, we can not restore its brilliance;

  likewise if you try to treat it with an iron.

  The local dullness of the layer is therefore irreversible; so she offers a bet

  safe evidence against forgery by scrubbing or scraping.

COMPARATIVE EXAMPLE:

  A sheet of white paper is coated on each of its faces with an aqueous pigmented composition containing 5 parts of kaolin per 1 part of binder (latex styrene butadiene). The layer obtained is white.

  do not grill the sheet and this one is matte.

  Each side is printed by laser printing.

  We try to erase some printed characters; the characters disappear and moreover it is not possible to detect with the naked eye a dullness difference on the gummed part and the unglazed part This paper can therefore be

  easily falsified without falsification being detected.

EXAMPLE 2

  A watermarked paper is used which contains in bulk reagents (ferric chloride and precipitated manganese ferrocyanide) and one or more disperse organosoluble dyes, these products being intended to give the paper the sensitivity to acids and solvents which can be used to falsify by chemically the paper and whose surface was treated in gluing press using a solution containing pyranine in order to

  -ensitize the paper with eraser.

  This paper is layered with the previous layer of Example 1; the amount

  deposited in dry weight is 12 g / m 2 per side.

  The paper thus coated is calendered so as to obtain a gloss of 30,

measured as in Example 1.

  On the sheet obtained, a general impression is made by offset and particular mention is made by laser printing and a signature at

ink pen.

  1 o If we try to erase or scratch any of the prints or writings, the layer becomes matte; it is observed that there was attempt to falsify As in Example 1, we verify the irreversibility of the

  dullness taken locally by the layer.

  In transmitted light, although there is one layer on each side of the paper,

  we always observe the watermark that allows to authenticate the document.

  If you try to erase the signature with an eraser pen or

  alkaline sulfur reducers, a fluorescent yellow spot develops.

  If one tries to falsify the impressions or writing with solvents or acids, it develops colored spots The invention thus allows

  to obtain a sheet having a very high degree of security.

EXAMPLE 3

  As in Example 1, a sheet of white paper is coated on each of its faces with an aqueous pigmented composition containing 5 parts of kaolin per 1 part of binder (latex styrene butadiene). The layer obtained is

white.

  The weight of deposited layer, in dry, is 14 g / m 2 per face.

  sheet thus coated so as to have an average gloss of 60.

  Each side is printed using an impact printer.

  We try to erase some printed characters; the characters disappear

  in part, but the layer loses its shine (the layer is not destroyed, however). The difference in shininess of the layer at the point of falsification is thus easily observed with the naked eye.

  Similarly if we try to scratch with a blade some characters

  printed, the gloss disappears If we try to rub with a woolen cloth the part become matt, we can not manage to restore its brilliance; likewise if you try to treat it with an iron.

Claims (6)

  Security or bank note sheet, tamper-proof by mechanical processes characterized in that it is coated, at least in the places that will bear the prints and / or the scriptures to be protected, with a shiny layer that becomes matt when it is subjected to a scrubbing action or scratching.   2 sheet according to claim 1, characterized in that the layer has a gloss, measured by determination of gloss at 75 degrees according to TAP method Pl 480 om-85, greater than or equal to 25   Sheet according to Claims 1 and 2, characterized in that the   glossy layer contains at least coating pigments and at least one binder.   Sheet according to Claims 1 to 3, characterized in that   contains chemical tampering agents and / or chemical elements authentication.   Sheet according to Claim 4, characterized in that the chemical tampering agents and / or the authentication elements are under and / or in the glossy layer.   Sheet according to one of Claims 1 to 5, characterized in that   the base support is white or colored.   7 Document of security or value characterized by the fact that it is obtained   from a sheet according to claims 1 to 6.